1. Field of the Invention
The invention relates to nuts; and, more particularly, to a nut having a sleeve lock adapted to retain the nut to a panel while allowing for variations in panel thickness.
2. Description of the Prior Art
Quick action fasteners are well known in the art. These fasteners are used in aircraft panels having holes of certain diameters. Such fasteners in the prior art, and most flush head-type bolts, have a countersunk opening in the head thereof configured to a tool, such as a hex opening for receiving therein an Allen-type tool, whereby the tool can be inserted into the opening and the bolt rotated to install or remove the same.
In normal aircraft installations, particularly those involving panels of composite materials, there is a preset hole diameter into which such fasteners are to be installed. The fastener assemblies to be installed in such panels include a nut having an enlarged head disposed in a countersunk surrounding the hole, the nut having an elongated shank extending through the hole to the other side of the panel. In order to fixedly secure such nuts to the panel for non-rotation, it is necessary that such nuts be somehow locked to the underside of the panel, as by swaging of the shank. Nuts that are installed by means of expansion or collapsing are not suitable for use in composite panels as the installation operation can cause cracking or fissures in the panel; thus, such swaging can cause cracks, particularly in panels of composite material, and it is difficult to compensate for panels of varying thicknesses using nuts of predetermined shank lengths.
There is thus a need for a fastener assembly wherein the assembly accommodates itself to panels of varying thicknesses into which the nut thereof is installed in a non-rotating manner and relieves stresses in such panels surrounding the hole in which the nut of the fastener assembly is installed.